Orally administered medicaments are given to the patient in many forms, including solid form such as capsules, caplets or tablets and liquid form such as solutions, emulsions or suspensions. Medicaments administered in solid form are usually intended to be swallowed whole, therefore, the often disagreeable taste of the active ingredient need not be taken into account in formulating the medicine, except for the provision of means to prevent the taste from being apparent during the short time the medicine is in the mouth. Such means may include the provision of an appropriately thin and quickly dissolving coating on a tablet or caplet or the use of a gelatin capsule form, (the gelatin outer shell of the capsule keeps the active ingredient inside until the capsule has been swallowed), or simply compressing a tablet firmly so that it will not begin to disintegrate during the short time that it is intended to be in the mouth.
Children, older persons, and many other persons including disabled or incapacitated patients have trouble swallowing whole tablets and even capsules. Therefore, in cases where the dosage to be administered cannot be made into a very small tablet or capsule, it is desirable to provide the medicine either in a chewable solid form or a liquid form. For many patients, including pediatric and geriatric patients, a liquid oral dosage form is preferable over chewable dosage form because of the ready swallowability without chewing of the liquid dosage form.
A common problem associated with liquid dosage forms is the often disagreeable taste of the active ingredients which manifest itself during the time that the liquid dosage form is in the mouth prior to swallowing. In some cases, the taste of the active medicament in a liquid form is generally overpowered by adding flavoring ingredients to the liquid so that when it is swallowed the bitter or unpleasant taste of the medicament is masked. For instance, this has been done with a pediatric liquid dosage form of acetaminophen (N-acetyl para-aminophenol or "APAP"). APAP is available commercially in an aqueous solution that includes overpowering flavor ingredients that masked the unpleasant taste of the APAP.
Aqueous solutions are generally stable and easy to prepare for water soluble actives, such as APAP, but it is difficult to prepare water insoluble pharmaceutical actives in storage stable ready-to-use liquid dosage form. Water insoluble ingredients present in water based solutions tend to separate or settle out and even shaking before administration does not insure a consistently accurate dosage regimen. While some water insoluble medicaments are soluble in alcohol, and may be presented in alcohol solutions, it is more desirable, particularly in pediatric dosage forms, to use aqueous "alcohol free" solutions.
The present invention is directed to discovery of a stable aqueous suspension system for water insoluble pharmaceutical actives which when combined with taste masking compositions achieve a palatable dosage form for both geriatric and especially pediatric applications.